Software-based logic simulation and/or design tools, also referred to as electronic design automation (EDA) tools or computer aided design (CAD) tools, are capable of performing various circuit design tasks. Circuit designs can be specified in a programmatic form, i.e., using a hardware description language such as VHDL or Verilog. Hardware description languages permit hardware designers to define signals at a very high level of abstraction which can be translated, by the design tool, into actual pins and circuitry for a target device such as a programmable logic device (PLD). The design tool further can perform an analysis of the circuit design with respect to timing, functionality, and power consumption, and provide such information back to the circuit designer.
In terms of power consumption, the design tool typically relies upon a model for each of the various components specified by the circuit design. Each model provides a procedure, or technique, for calculating an estimate of the power that likely will be dissipated by the corresponding physical circuit element when implemented on a target device. Evaluation of the models for the circuit elements in a circuit design can provide the designer with an estimate of the power consumption for the entire circuit design or target device.
Most power estimation techniques rely upon one or more assumptions regarding the circuit element being represented. These assumptions effectively are constants that do not account for the actual configuration of the circuit element as used within a particular circuit design, or the usage of the circuit element within that circuit design. In consequence, the accuracy of a power estimate for a single circuit element can range from being somewhat accurate to very inaccurate.
In view of the significant number of components in a circuit design, even small differences between estimated power consumption and actual power consumption for a single component, when compounded over the entire circuit design, can lead to significant errors in estimating overall power consumption. Thus, accurate power estimation at the component level is important not only with respect to evaluating performance of individual circuit elements, but also for evaluating power consumption of the circuit design as a whole.